As circuit electrode widths and circuit electrode spacings have become extremely narrow with increasingly higher densities of circuits used in the field of precision electronic devices in recent years, circuit-bonding methods for such circuits have been desired that have reliability equivalent or superior to conventional reliability.
With circuit bonding, incidentally, and particularly with bonding of circuit electrodes formed on flexible wiring boards to circuit electrodes formed on other circuit members, folding of the flexible wiring boards has posed the risk of cracking the circuits on the flexible board, thus causing wire breakage. Circuit-bonding methods have therefore been developed wherein, on a flexible board with circuit bonded sections that are bonded using an anisotropic conductive film for circuit connection, a circuit-protecting member (solder resist) is provided at the sections of circuit electrodes outside of the circuit-bonded sections to protect those sections, and during circuit bonding between circuit electrodes on the flexible board and circuit electrodes on a glass substrate with an anisotropic conductive film for circuit connection, the anisotropic conductive film for circuit connection is also attached to a part of the circuit-protecting member in addition to the circuit-bonded sections (see Patent document 1, for example). According to this circuit-bonding method, the circuit electrodes on the flexible board are protected by the circuit-protecting member and anisotropic conductive film for circuit connection, thus helping to prevent wire breakage of the circuit electrodes on the flexible board and producing high bonding strength between the circuit electrodes.    [Patent document 1] Japanese Unexamined Patent Publication No. 2002-358026